i want to bring in nbc news correspondent adrian mung who is in moscow for us to pick up the story from there. adrian, what, if anything, do we know about that trip to russia last year? >> reporter: well, good day. it's still unclear whether the elder son tamerlan, actually did meet someone suspicious. we know that he was with his father. his father has spoken at length about both sons actually. he did confirm the man did come out and visit and stayed with them. both parents have actually said that they believe both sons, the 26-year-old tamerlan, now deceased, and the 19-year-old dzhokhar, the one who's in custody in the hospital, they say that they were framed. and the mother has actually accused the fbi of regularly harassing the family. she says because they are chechens, ethnic chechens. now, the parents have been living more recently in dagestan which is in the north caucuses region. now, this is a very troubled area. it's a small russian republic, but it's neighboring chechnya. both of these areas have seen a lot of conflict, particularly an active separatist group in dagestan ri